Atherosclerotic lesions develop from fatty streaks in the intimal layer of arteries and are characterized by accumulation of cholesterol laden foam cells. Macrophages convert to foam cells by the uncontrolled accumulation of oxidized LDL, taken up via the scavenger receptor. Drugs specifically inhibiting this receptor could halt plaque progression, presenting a novel approach in treating atherosclerosis. The ultimate objective of this project is the discovery of small molecule inhibitors of scavenger receptor transcription by screening over 100,000 chemicals using our proprietary robotics in a high-throughput screen. In Phase I 4.5kb of 5' flanking region of the scavenger receptor gene was used to prepare promoter-luciferase reporter constructs. As a control, the LDLr promoter was synthesized by PCR and a promoter luciferase reporter vector constructed. In Phase II, stable cell lines containing the scavenger receptor.luciferase reporter will be isolated and the high-throughput screen initiated. In parallel, to ensure all regulatory transcription sequences are obtained, we will generate a second reporter construct, designed for integration at the site of scavenger receptor locus in the genome. Lead compounds will be evaluated in secondary assays by quantitative PCR and their ability to inhibit the accumulation of oxidized LDL by macrophages.